Telephone receiver



J. B. G UMAER TELEPHONE RECEIVER Filed sept, 1e, 1922 vns Patented June 30,- 1925.

UNITED"u STA JACKSON B. GUMAER, 0F KANSAS CITY, MISSOURI.

TELEPHONE RECEIVER.

To all whom t may concern:

Be itl known that I, JACKSON B. Gunmen, acitizen of the United States, residing at Kansas City, in the county of Jackson and State of Missouri, have invented certain new and useful Improvements in Telephone Receivers, of which the following is a speciication.

This invention relates to telephone receivers and more-particularly to aA receiver having a diaphragm fixed at the center and movable at the circumference.

An object of the invention is the provision of a receiver of this type in which thel diaphragm may be readily adjusted.

A further object is the provision of a cup and central magnet construction which may be readily and quickly assembled.

A further objectl is the provision of a simple, durable receiver of relatively few parts. i

In the accompanying drawings I have of the invention.

shown one embodiment In this showing,

Figure l is a perspective, View,

Figure 2 is a central vertical sectional view, y

Figure 3 is a horizontal sectional view on line l-S of Figure 2,

VFigure 4 is a similar view on line ll-i of Figure 2, and,

Figure 5 the magneticy 'circuit or path.

Referring to the drawings, the reference numeral 1 designates the magnetic cup of the receiver which is formed of suitable material preferably steel, in order to retain a high degree of residual magnetism. A central magnet 2 is mounted in the cup. The central magnet is preferably formed of soft magnetic metal such as wrought iron. As shown, the opening and the lower portion of the central magnet is threaded as at 3 and adapted to be received in the opening in the cup. A diaphragm 4 is mounted on the upper end of the central magnet by a screw or bolt 5. As shown the diaphragm extends over the upper edge of the cup forming an air gap 6.

An electromagnet coil 7 is arranged is a diagrammatic view showing Application filed September 18, 1922. Serial N'o. 588,944.

around the center magnet, the coil being main circuit are also secured to these binding` posts. These wires pass through av suitable opening 14 in the cup. The upper end of the cup is provided with a threaded portion 15 adapted to receive tl'ie ,usual rubber or composition ear-piece 16. l

The, operation of the device will. be apparent from the foregoing description. The

magnet 7 is energized by current from the lead wires 13 forming a magnet flux indicated bythe arrows in Figure 5 of the drawings. This flux Hows through the center magnet 2, the diaphragm 4 and the walls lthrough the ear-piece l() in the usual inancup is provided with a threaded' ner. -It will be apparentthat the sir/.e of the air gap may beI adjusled by moving the center magnet 2 in the cup and .thus changing the'position of the diaphragm.

It is to be understood that the form of my invention herewith shown and described is to be taken as a preferred example of the saine, and that various changes inthe shape, size, and arrangement of parts may beresorted to without departing from the spirit Aof the cup 1. Energizationof the walls of y of the invention or the---scope of the sub-v A joined claims.

Having described my invention, I claim: 1. A telephone receiver comprisingV an electromagnet, a casing surrounding said magnet, said casing being formed of conducting material Ito form a path for the magnetic flux, a diaphragm arranged above said casing and spaced from the upper edge l thereof, said diaphragm having alfixed centerand movable edges and a cover arranged other end of said core, the free edges of said on said casing over. said diaphragm. diaphragm being disposed adjacent said cup. l0

2; A receiver comprising a `cup having a In testimony whereof I aiix my signature threaded opening, a core arranged Within in presence of two Witnesses.

' 5 said cup, one end of said core being threaded JACKSON B. GUMAER.

and received 1n Asaid opening, an e'iectro- Witnesses: i l magnet surrounding said Vcore, and p a- P. E. SALDIEN,

diaphragm having its center seeilred to the TQ P.' SALDIEN. 

